It is known that 2-methoxycarbonyl-4-chlorotrifluoromethane-sulfonanilide can be used as an active ingredient of an insecticidal/acaricidal composition in Japanese Laid-open Patent Nos. sho-57-156407A and hei-8-319202A. However, its insecticidal/acaricidal effect may be insufficient when used as a formulation such as oil solution, aerosol and the like.